The present invention generally relates pedestrian platforms, walkways and sidewalks and more particularly to pedestrian platforms, walkways and sidewalks for the blind and visually impaired.
There is often the need, in public transit facilities, for pedestrians to detect the location of a platform or other potential hazards. By making the pedestrian aware of a potential hazard, they may avoid the hazard. By way of example, this may include railroad crossings, subway platforms, loading docks, stages, stairways, sidewalks, curb ramps, crosswalks, man holes, potholes, etc.
Americans with Disabilities Act (ADA): “Accessibility Guidelines for Buildings and Facilities” set the requirements for the use of detectable warnings at curb ramps, walking surfaces, transit platforms and the like to warn visually impaired people of hazards. The guidelines require that detectable warnings shall consist of truncated domes with a diameter of nominal 0.9″ (23 mm), a height of nominal 0.2″ (5 mm) and a center-to-center spacing of nominal 2.35″ (60 mm) and shall contrast visually with adjoining surfaces, either light on dark or dark on light. The material used to provide contrast shall be an integral part of the walking surface. Detectable warnings use on interior surfaces are required to differ from adjoining surfaces in resiliency or sound-on-cane contact. Platform edges bordering a drop off and not protected by screens or guard rails shall have a detectable warning 24 inches wide running the full length of the platform drop off.  If a walkway crosses or adjoins a vehicular way, and the walking surface is not separated by curbs, railing or other element between the pedestrian areas and the vehicular areas, the boundary between such area is to be defined by a continuous detectable warning 36 inches wide. Curb ramps are also required to have detectable warnings extending the full width and depth of the curb ramp.
Known within the art are tiles designed to be glued or mechanically fastened to the existing walking surface. U.S. Pat. No. 4,715,743 issued to Schmanski discloses a uniform adhesive layer applied to a tile, which is then adhered to a surface. Tiles installed according to this method are not flush with the ground and may come undone.
Also known within the art is the use of a patterned tool to produce a durable tactile warning surface for sidewalks and other walkways including pouring a concrete base, applying pigmented or colored hardener to the upper surface of the concrete base and stamping the upper surface of the converter base with a patterned tool. This can be very costly, incurring labor costs due to the waiting periods between pouring and stamping and the requirement of on-site labor to perform the stamping. Also, there is a great deal of room for imperfections and error.
Adherence of the tile to a walkway surface is a critical aspect of the present invention. Prior efforts to retain the tile in an attached position have been frustrated by separation of the peripheral edge of the tile from the pavement. Prior attempts to solve this problem have included the stamping of concrete, plastic tiles with chamfered edges and the like. However, as discussed previously, stamping is costly, prone to errors, labor intensive and requires on site work. Plastic tiles are much more fragile and subject to lifting and coming undone.
Accordingly, what is needed is a textured tile system and method of installation that allows for pre-cast tiles to be easily installed, that abut the edge of the walking surface, do not require labor intensive on-site stamping, provides fewer  imperfections, is in compliance with the ADA and may freely move relative to one another.